Forces loyal to Syrian President Bashar al-Assad are intensifying their offensive over key rebel-held towns in the southern province of Deraa.
Thousands of people have continued to flee the area.
Clashes broke out on Tuesday between pro-government forces, which have amassed on the outskirts of the town of Basr al-Harir, as fighting between the two sides escalated.
At least 200 air strikes and 150 barrel bombs targeted Basr al-Harir this morning .